1. Technical Field
The present invention relates to a lens barrel, a replacement lens, an imaging device, and a control program.
2. Related Art
A lens barrel is known that includes a focus limiter for limiting an optical system such that the optical system can only move within a specified range.
Furthermore, an imaging device is known that judges whether the current position of a focus lens is at an end of a search range and, when it is judged that the focus lens is at the end of the search range, sets the movement direction to be a direction toward the opposite end of the search range and begins moving the focus lens.    Patent Document 1: Japanese Patent Application Publication No. 2001-042419    Patent Document 2: Japanese Patent Application Publication No. 2014-038197
If the movable range of the optical system is limited by the focus limiter, regardless of the settings of the camera body, the replacement lens drives the focus lens unit within the limited range. At this time, information concerning the focus limit cannot be transferred between the replacement lens and the camera body, and there are cases where control for effectively utilizing the settings of the camera body cannot be realized. (First Problem)
Conventionally, the focus lens unit and the focus limiter are mechanically linked. Therefore, it is impossible to establish both a manual focus operation and a focus limit. (Second Problem)
When the camera body instructs the replacement lens concerning the movement direction of the focus lens unit according to the current position of the focus lens unit, the replacement lens continues moving the focus lens unit according to the most recent instructions until new instructions are received. When the camera body determines that the focus lens unit has reached the end of the preset range, based on the current position of the focus lens unit, the camera body transmits stop instructions to stop the movement. Therefore, at the timing when the replacement lens stops the movement of the focus lens unit according to the stop instructions, there are cases where the focus lens unit is already beyond the preset range. (Third Problem)